1. Field of the Invention
The present invention relates to an apparatus for extruding and cutting resin strands, and more particularly to an apparatus for extruding and cutting resin strands which has a configuration capable of achieving an accurate and easy initial setting for a desired angle of a cooling plate with respect to a cutting unit within a reduced period of time while minimizing the amount of cold water used and eliminating use of any cold water distributor, thereby reducing the manufacturing costs.
2. Description of the Prior Art
A variety of resin extruding and cutting devices are known which are configured to extrude a thermoplastic resin material into continued strands, to cool the extruded strands, and then to cut the strands into small pieces in the form of grains while drying them.
Referring to FIG. 6, an example of a conventional resin extruding and cutting device is illustrated which is disclosed in Japanese Laid-open Patent Publication No. Sho. 60-97806. This resin extruding and cutting device has features in that a water drain port is provided at a cooling plate. As shown in FIG. 6, the resin extruding and cutting device includes a resin extruding unit 71 for extruding a resin material into continued strands, and a resin cooling unit 72 for cooling the strands extruded from the resin extruding unit 71. The resin cooling unit 72 includes a cooling plate 721 arranged in the vicinity of an outlet of the resin extruding unit 71 and adapted to spray cold water onto the strands emerging from the resin extruding unit 71 while feeding those strands from an upstream end thereof to a downstream end thereof, thereby cooling the strands, a drain duct 722 connected at an inlet thereof to the cooling plate 721 near the downstream end of the cooling plate 721 and adapted to drain the water, used to cool the strands, into a water receiving reservoir 723, and a suction duct 724 connected to the cooling plate 721 near the downstream end of the cooling plate 721 and mounted with a suction fan 725 to remove moisture from the strands emerging from the cooling plate 721. The suction duct 724 is open to the water receiving reservoir 723 at an outlet thereof. The resin extruding and cutting device also includes a cutting unit 73 mounted at the downstream end of the cooling plate 721 and adapted to cut the strands emerging from the cooling plate 721 into small pieces of a desired length, a collecting hopper 74 arranged beneath an outlet of the cutting unit 73 and adapted to collect the small pieces discharged from the cutting unit 73, and a drying duct 75 connected to the collecting hopper 74 and adapted to dry the small pieces discharged from the collecting hopper 74 while feeding them to a storage tank. Cold air from an air supply source (not shown) is blown into the drying duct 75.
In the conventional resin extruding and cutting device having the above mentioned configuration, resin strands extruded from the resin extruding unit 71 are cooled by cold water sprayed in the cooling plate 721 while passing through the cooling plate 721, and then introduced into the cutting unit 73. The cooled resin strands are cut by the cutting unit 73 into small pieces of a desired length which are, in turn, discharged into the collecting hopper 24. The small pieces are then fed from the collecting hopper 24 to the storage tank via the drying duct 75 while being dried by cold air flowing along the drying duct 75.
In order to allow the strands to be substantially free of moisture before entering the cutting unit 73, the water used to cool the strands is drained from the cooling plate 721 through the drain duct 722. The moisture attached to the strands are also removed from the strands by a sucking force from the sucking fan 725, and then drained through the sucking duct 724.
However, the above mentioned resin extruding and cutting device involves a problem in that the cooling water once used is drained, for disposal thereof, into the water receiving reservoir, so that a large amount of water is wasted.
The strand emerging from the cooling plate 721 of the cooling unit 72 should enter between drawing rollers included in the cutting unit 73 under the condition in which the entering angle of the strand is adjusted in accordance with the characteristics and diameter of the strand. However, no means capable of achieving such an adjustment is provided at the conventional device. For this reason, there is a problem in that a large amount of cut products with a poor quality are produced.
Referring to FIG. 7, another conventional resin extruding and cutting device is illustrated. This device has features in that it includes a separate drier. As shown in FIG. 7, the resin extruding and cutting device includes a resin extruding nozzle 81 for extruding a resin material into continued strands, and a resin cooling unit 82 arranged near the resin extruding nozzle 81 to cool the strands extruded from the resin extruding nozzle 81. The resin cooling unit 82 includes a cooling plate 821 adapted to spray cold water onto the strands emerging from the resin extruding nozzle 81 while feeding those strands from an upstream end thereof to a downstream end thereof, thereby cooling the strands, a drain duct 823 connected at an inlet thereof to the cooling plate 821 near the downstream end of the cooling plate 821 and adapted to drain the water, used to cool the strands, into a water receiving reservoir 824, a column 825 hingably coupled to the upstream end of the cooling plate 821 at an upper end thereof to hingably support the cooling plate 821, and an extendable angle adjusting unit 827 hingably coupled to a middle portion of the cooling plate 821 at an upper end thereof and adapted to hingably move the cooling plate 821 about the upper end of the column 825 in accordance with an extension or retraction thereof, thereby adjusting the angle of the cooling plate 821. The resin extruding and cutting device also includes a cutting unit 83 mounted at the downstream end of the cooling plate 821 and adapted to cut the strands emerging from the cooling plate 821 into small pieces of a desired length. The cutting unit 83 includes drawing rollers 831 and cutters 832. The cutting unit 83 also includes a water supply pipe 833 for supply a flow of water to feed cut pieces from the cutter 832. The resin extruding and cutting device further includes a conveyor 84 arranged in the vicinity of the outlet of the cutting unit 83 at one end thereof and adapted to feed the cut pieces emerging from the cutting unit 83, and a drier 85 arranged at the other end of the conveyor 84 and adapted to dry the cut pieces fed by the conveyor 84.
In the conventional resin extruding and cutting device having the above mentioned configuration, the strand emerging from the cooling plate 821 of the cooling unit 82 should enter the cutting unit 83 under the condition in which the entering angle of the strand is adjusted in accordance with the characteristics and diameter of the strand. To this end, the extended length of the extendable angle adjusting member 827 is adjusted, thereby adjusting the angle of the cooling plate 821. Thus, the angle of the cooling plate 821 is set.
Resin strands extruded from the resin extruding unit 81 are sufficiently cooled by cold water sprayed in the cooling plate 821 while passing through the cooling plate 821, and then introduced into the cutting unit 83. In order to allow the strands to be stably introduced into the drawing rollers 831 of the cutting unit 83 while allowing a stable and reliable cutting operation of the cutting unit 83, the water used to cool the strands is drained, in a controlled amount, from the cooling plate 821 through the drain duct 823 before the introduction of the strands into the cutting unit 83.
The cooled resin strands are cut by the cutting unit 83 into small pieces of a desired length which are, in turn, discharged into the conveyor 84. The cut small pieces are fed along the conveyor 84 to a drier 85 using a flow of water supplied from the water supply pipe 833, and then dried in the drier 85. Thus, desired products are produced.
In this resin extruding and cutting device, however, it is difficult to accurately set a desired angle of the cooling plate because the cooling plate is heavy and has an integral construction. Furthermore, a lengthened setting time is taken.
Moreover, the set angle of the cooling plate may be easily varied during the operation of the device even due to small impact applied to the cooling plate. In this case, cut products of a poor quality may be produced.
The provision of the drain duct and water supply pipe results in a complexity in the entire water distribution arrangement. As a result, the manufacturing costs of the device are increased.
Although the drain duct is provided at its upper end with a drain plate for draining, in a controlled amount, the water used to cool the extruded strands, the drain plate rather causes problems. That is, it is difficult to achieve an easy manipulation and replacement of the drain plate because the drain plate is arranged within the interior of the cooling plate.
Therefore, the present invention has been made in view of the above mentioned problems, and an object of the invention is to provide a resin extruding and cutting apparatus having a configuration capable of reducing an initial setting time taken to set a desired angle of a cooling plate with respect to a cutting unit while achieving an accurate adjustment of the set angle using an inexpensive angle adjusting means.
Another object of the invention is to provide a resin extruding and cutting apparatus having a configuration capable of guiding cold water, used to cool extruded resin strands, to the interior of a cutter so that the guided cold water is used to feed cut pieces from the cutting unit, while being capable of allowing the extruded resin strands to be stably introduced between drawing rollers of the cutting unit.
Another object of the invention is to provide a resin extruding and cutting apparatus having a configuration capable of achieving an easy repair, cleaning and replacement of elements while allowing the amount of cold water drained after being used.
In accordance with the present invention, this object is accomplished by providing a resin extruding and cutting apparatus comprising a resin extruding nozzle adapted to extrude a resin material into strands, a cooling unit arranged in the vicinity of the resin extruding nozzle and supported by a base in an inclined state, the cooling unit serving to cool the extruded strands emerging from the resin extruding nozzle using cold water and having a bottom wall for feeding the strands to a downstream end of the cooling unit therealong, a cutting unit arranged in the vicinity of a downstream end of the cooling unit and adapted to cut the cooled strands, emerging from the cooling unit, into small pieces, the cutting unit including a body, a pair of drawing rollers rotatably mounted the body, a fixed blade fixedly mounted to the body, and a rotating blade rotatably mounted to the body, a conveyor inclinedly arranged at a downstream end of the cutting unit, and a drier arranged at a downstream end of the conveyor to dry the cut small pieces, further comprising: a strand guide unit arranged between the cooling unit and the cutting unit and adapted to guide the strands discharged from the cooling unit between the drawing rollers of the cut unit, the strand guide unit providing a strand guide surface for guiding the strands discharged from the cooling unit to a nip defined between the drawing rollers of the cutting unit; a level adjusting assembly mounted to the cutting unit in such a fashion that a level thereof is adjustable with respect to the cutting unit, the level adjusting assembly hingably supporting the strand guide unit in such a fashion that the strand guide unit is hingable with respect to the cutting unit while being adjustable in level with respect to the cutting unit so that the strand guide surface of the strand guide unit extends from the downstream end of the cooling unit to the nip defined between the drawing rollers; and water guide means for guiding the cold water, used to cool the strands in the cooling unit, to the conveyor so that the guided cold water is used as a flow of water adapted to feed the cut small pieces along the conveyor.